In clasps referred to as unfolding buckle or portfolio, one generally finds at least two rigid blades hinged to one another, the free end of each of such blades being fastened respectively to each strand exhibited by the bracelet. This is the case, for instance, for the clasp described in U.S. Pat. No. 1,796,341. In models of this type, the bracelet links are superposed on the folded back arms of the clasp in a manner such that the bracelet exhibits a greater thickness at the place of such clasp.
The bracelet clasp described in the patent document DE-A-3 520 122 likewise includes two plates which are folded one over the other and each of which is attached to a bracelet strand formed of links. In this model, at least one of the two plates includes two elements which may slide in a telescopic manner within one another and in the longitudinal direction of the bracelet. In this manner, and although the clasp includes only two plates, such clasp may be extended, once opened, over a distance greater than that of the sum of the lengths of each of the plates. This system enables shortening the rigid portion exhibited by the bracelet in the closed position while permitting a great extension of the latter in the open position. However, in spite of the advantages set forth hereinabove and that one will find partially in the present invention, one strand of the bracelet of the cited document is also located superposed on the clasp in the closed position, thus creating an apparent greater thickness.
Finally, it will be noted that a clasp including three elements sliding relative to one another in order to constitute a telescopically extensible clasp is described in the U.S. Pat. No. 1,801,963. However, no link of the bracelet covers this clasp and even if one were to apply to said clasp the teaching of documents U.S. Pat. No. 1,796,341 or DE-A-3 520 122, such links would allow the clasp to appear once such clasp was retracted in its closed position.
The bracelet of this invention mitigates the cited difficulty in retracting the clasp within the thickness of the bracelet links in a manner such that said bracelet appears to be without a thickness discontinuity at the place of the clasp, such clasp exhibiting furthermore a closed rigid portion of reduced length while permitting a great elongation of the bracelet in the open position.